140 Transactions of the Society. 



I now come to the great class of the Protozoa, and I will take 

 first an organism found in the blood of a monkey (a spirochete) 

 which belongs to the so-called Proflagellata, and is, I should 

 imagine, not yet quite sure of its place. It was formerly a plant, 

 and now has been advanced, but its exact position has not yet been 

 determined. The spirochetes are important as being the cause of 

 such diseases as relapsing fever, tick fever, and syphilis. They are 

 found in the mouth and other body cavities, where they are mostly 

 harmless ; on ulcerated surfaces and inflamed mucus membranes ; 

 as parasites of the tissues, as in syphilis ; or of the blood, as in 

 relapsing fever. 



This particular one was found in the blood of a monkey {Cerco- 

 pithecus sahtvus), and is of the type of Spirochxta recurrentis, the 

 cause of relapsing fever which is believed to be conveyed by the 

 common, bed-bug. This used to be called Spirillum Ohermeieri, after 

 Obermeier, who discovered it in 1373, and who died from its effects 

 after inoculating himself with it in order to study the disease. He 

 was the first of the modern scientific martyrs. 



SPIBOCHiETA. 



Habitat Character 



Oreen Monkey — Cercopithecus sahxus . . Sierra Leone Like sp. reciirrentis 



The next in order are the Flagellates, and I will take first the 

 Trypanosomes, which are flagellated organisms living in the blood 

 sernm. They are the cause of many deadly diseases in man and 

 animals, and they are transferred from animal to animal by biting 

 flies, fleas, lice, and leeches. Probably in these carriers the sexual 

 part of tlieir life-cycle takes place. They kill in different ways, 

 according as the effects produced by them are acute or chronic. 

 Many acute trypanosome infections, in which the number of 

 organisms may rise to as many as 3,000,000 per c.mm. of blood, 

 cause death mechanically, in the same way as in some pernicious 

 malarias, by the cerebral capillaries getting plugged with amceboid 

 forms of the organism. The chronic infections cause death, as in 

 sleeping sickness, by causing a cellular exudation round the vessels 

 of, and slow changes in, the brain and nervous systems. 



I have found trypanosomes in 50 mammals of two species, 

 in 7 birds and 3 amphibia of seven and three species respec- 

 tively, in nine of these species, for the first time; 49 of the 

 mammals were ordinary rats, out of 500 examined for another 

 purpose, in which the ordinary rat-trypanosome, Trypanosoma 

 Leivisi, was found. The other mammal was a Fat Mouse {Steatomys 

 pratensis) from Soutli Africa, in which trypanosomes have not 

 hitherto been described. This one was like the Nagana trypano- 

 some, but as I could not carry it on, it is impossible to do more 

 than record its presence. The bird trypanosomes are all new in 

 these particular birds, but I believe them to belong to the general 



